Skip the structure analysis when a phase-stability check is disabled

calphy/phase.py

@@ -554,6 +554,11 @@ def check_if_melted(self, lmp, filename):
         aborted with a MeltedError.  Detection can be turned off by setting
         ``tolerance.solid_fraction: 0``.
         """
+        # Disabled (solid_fraction <= 0): the comparison below can never fire, so do not run the
+        # structure analysis at all. It is not free, and pyscal3 can segfault in find.neighbors on
+        # some LAMMPS triclinic dumps, killing a run over a check that could not have stopped it.
+        if self.calc.tolerance.solid_fraction <= 0:
+            return
         solids = ph.find_solid_fraction(os.path.join(self.simfolder, filename))
         if solids / self.natoms < self.calc.tolerance.solid_fraction:
             self.lammps_close(lmp=lmp)
@@ -569,7 +574,11 @@ def check_if_solidfied(self, lmp, filename):
 
         If the solid fraction in ``filename`` exceeds
         ``tolerance.liquid_fraction`` the run is aborted with a SolidifiedError.
+        Disabled (``liquid_fraction >= 1``), the analysis is skipped, as in
+        ``check_if_melted``.
         """
+        if self.calc.tolerance.liquid_fraction >= 1:
+            return
         solids = ph.find_solid_fraction(os.path.join(self.simfolder, filename))
         if solids / self.natoms > self.calc.tolerance.liquid_fraction:
             self.lammps_close(lmp=lmp)

tests/test_disabled_phase_checks.py

@@ -0,0 +1,46 @@
+"""A disabled phase-stability check must not run the structure analysis.
+
+`tolerance.solid_fraction: 0` (or `liquid_fraction: 1`) makes the comparison in
+check_if_melted / check_if_solidfied impossible to trigger, but the solid fraction
+was still computed with pyscal3 -- which segfaults in find.neighbors on some LAMMPS
+triclinic dumps (Mg2Si antifluorite, 60-degree primitive cell), killing the run.
+"""
+from types import SimpleNamespace
+
+import pytest
+
+import calphy.phase as phase_mod
+from calphy.phase import Phase
+
+
+def _fake(solid_fraction=0.0, liquid_fraction=1.0):
+    tol = SimpleNamespace(solid_fraction=solid_fraction, liquid_fraction=liquid_fraction)
+    return SimpleNamespace(calc=SimpleNamespace(tolerance=tol), simfolder="/nonexistent", natoms=10)
+
+
+def _explode(_):
+    raise AssertionError("find_solid_fraction must not be called when the check is disabled")
+
+
+def test_disabled_melt_check_skips_structure_analysis(monkeypatch):
+    monkeypatch.setattr(phase_mod.ph, "find_solid_fraction", _explode)
+    Phase.check_if_melted(_fake(solid_fraction=0.0), lmp=None, filename="traj.temp.dat")
+
+
+def test_disabled_solidification_check_skips_structure_analysis(monkeypatch):
+    monkeypatch.setattr(phase_mod.ph, "find_solid_fraction", _explode)
+    Phase.check_if_solidfied(_fake(liquid_fraction=1.0), lmp=None, filename="traj.temp.dat")
+
+
+def test_enabled_melt_check_still_runs(monkeypatch):
+    called = []
+    monkeypatch.setattr(phase_mod.ph, "find_solid_fraction", lambda f: called.append(f) or 10)
+    Phase.check_if_melted(_fake(solid_fraction=0.7), lmp=None, filename="traj.temp.dat")
+    assert called == ["/nonexistent/traj.temp.dat"]
+
+
+def test_enabled_solidification_check_still_runs(monkeypatch):
+    called = []
+    monkeypatch.setattr(phase_mod.ph, "find_solid_fraction", lambda f: called.append(f) or 0)
+    Phase.check_if_solidfied(_fake(liquid_fraction=0.05), lmp=None, filename="traj.temp.dat")
+    assert called == ["/nonexistent/traj.temp.dat"]